如何在Spring Data Jpa中查询@JoinTable？

Question

I used the Type filter in BookRepository, but it's not work.

Book.java

@Entity
public class Book {
    private Long id;
    private String name;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinTable(
            name = "book_type",
            joinColumns = @JoinColumn(name = "book_id"),
            inverseJoinColumns = @JoinColumn(name = "type_id")
    )
    private Type type;

    // getter and setter
}

Type.java

@Entity
public class Type {
    private Long id;
    private String name;

    @OneToMany(fetch = FetchType.LAZY)
    @JoinTable(
            name = "book_type",
            joinColumns = @JoinColumn(name = "type_id"),
            inverseJoinColumns = @JoinColumn(name = "book_id")
    )
    private Collection<Book> books;

    // getter and setter
}

BookRepository.java

@Repository
public interface BookRepository extends JpaRepository<Book, Long> {
    Page<Book> findBookListByType(Type type, Pageable pageable);
}

Is not Spring Data Jpa does not support this feature.

Answer 1

Try this

@Repository
public interface BookRepository extends JpaRepository<Book, Long> {

    @Query(value="Select b from Book b where b.type = :type")
    Page<Book> findAllByType(@Param("type") Type type, Pageable pageable);

}

Answer 2

由于您只有一个@OneToMany关联，您可以将 FetchType 更改为 EAGER。